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Re: operators


  Yes. A good exposition is in a book by Dimitri
VVedensky, just published by Addison-Wesley,
titled "Partial Differential Equations with
Mathematica". I take the following from the
introduction:
u := {r,theta,phi}
h := {1,r,r Sin[theta]}
Where the entries must be in the same order.
The Jacobian, J, is
J = h[[[1]]h[[2]]h[[3]]
and the gradient is given by
Grad[f_] := Table[D[f,u[[i]]]/h[[i]],{i,3}]
and the divergence by
Div[f_] := (1/J)Sum[D[(J f[[i]])/h[[i]],
		u[[i]],{i,3}]
I have not used these myself, and retyped them by
hand. But, they certainly look correct.
  Incidentally, I have just noticed that there
is also a package "Calculus`VectorAnalysis`"
that has all of this and a lot more premade.
  The package is desscribed in the technical
report "guide to Standard Mathematica Packages".
We get  a copy in every MMA box we get for 
the Macintosh.
  Hope this helps. Good luck.

Ronald D. Notestine
Faculty of Management
Chukyo University
Nagoya, Japan
ronald at sccs.chukyo-u.ac.jp
fax: 81-52-835-7196





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